Obesity, Sedentary Behavior Not Linked to Parkinson’s Disease Risk, Study Shows

Increased body mass and sedentary behavior do not increase the risk of having Parkinson’s disease, a study shows.

To date it is still not fully understood what causes Parkinson’s disease, but several environmental and lifestyle factors have been suggested as contributors to this disease.

In the study, “Body mass index, sitting time, and risk of Parkinson disease,” which was published in the journal Neurology, researchers from the Karolinska Institutet in Sweden focused on the potential of body mass index (BMI) — a measure indicative of obesity — and sitting time to contribute for Parkinson’s disease development and progression.

The team already had reported that more physical activity around the house and commuting lowered Parkinson’s risk. “Regardless of time spent on physical activity, sedentary behavior characterized by sitting extended periods of time has been associated with increased general morbidity and mortality,” the researchers wrote. “Thus, sedentary behavior may affect PD pathogenesis through mechanisms other than physical activity.”

Clinical records of 41,638 individuals who completed a comprehensive questionnaire with extensive assessment of lifestyle factors at a national fund-raising event in September 1997 (The Swedish National March Cohort) were analyzed.

During the study period (13 years) 286 participants were diagnosed with Parkinson’s disease.

Participants who spent six or more hours seated per day had a 6 percent higher risk. Also, those with body max index of 30 or higher had a 13 percent increased risk compared to leaner patients. These results were not found to be influenced by age, sex, or smoking status.

Although some differences were found, these data do not show a significant correlation between baseline body mass and sitting time with the risk of developing Parkinson’s, which is in accordance with previous studies.

However, researchers highlighted that all the analysis was based in data collected at the beginning of the study, and some measures could have changed during follow-up. “If such changes are related to the outcome, this could lead to misclassification and an over- or underestimation of any true association,” they wrote.

Still, it is widely accepted that the underlying mechanisms of Parkinson’s start many years before symptom onset. So, any factor that might contribute to development of this disease may occur in an “exposure window of interest closer to the baseline exposure assessment,” they said.

“Future studies should focus on environmental factors other than obesity and sedentary time in efforts to disentangle the complex causation of Parkinson’s disease,” the authors suggested.